Rangers recover the body of a gorilla killed in Virunga National Park in 2007. Photograph: WildLifeDirect

The killing of a gorilla is a disaster for us. When a silverback is habituated, it's worse. A habituated gorilla is extremely trusting and will let a human being approach to almost touching distance. They don't stand a chance against poachers, unless we can protect them. The habituation is for tourism, which generates revenue for the local community – their support is one of the main reasons that we have managed to protect them.

In January, we received news from Bukima that the Silverback from one of our habituated groups had been shot by a rebel group poaching in the Park. The killing happened less than 600 metres from our abandoned patrol post at Bikenge, now occupied by rebels. A local farmer was ordered to help the rebels collect the meat of the gorilla. He told them that the meat was dangerous to eat, and immediately informed us of the incident.

It was one of three possible solitary silverbacks that we have in DRC, and we really wanted to know which one had been killed by the rebels. To retrieve the body, I needed to get UN protection because the military from the 13 battalion who were occupying the Patrol Post at Bukima had entered the gorilla's habitat and started to cut it down to make charcoal. If we didn't do something quickly, it could be a disaster for the gorillas.

I wanted to send my rangers in to stop the military from cutting down the forest, but last time I tried to stop them, they shot at me. Then they arrested me, threw me in their prison and had me flogged 65 times until I was bleeding. The military commander responsible has now been sent to Kinshasa, so I decided to try and meet the new military commander in the hope he would be more willing to work with us and control his men.

But soon after some of our rangers on patrol were attacked by armed men at Bivumo, about 4kms from the Kakomero Patrol Post inside the Park. They captured one of the rangers and took his weapon after tearing up his identity card. According to the rangers, these men were Rwandan soldiers. As soon as they returned to the Patrol Post they informed the Congolese military stationed at Rugari who, assisted by the rangers, went in pursuit of them. Unfortunately it was already too late – only traces were found. The ranger was later released and he is in good health.

We then received more bad news from some of our rangers who live near Bikenge. Very recent gorilla remains were said to have been found about 1km from where the last was killed. Local people reported that its body was cut up and shoved down a pit latrine (this terrible act was done to humans during the Rwandan genocide). If this was true, I knew the gorilla was probably from the group Mapua.

With Robert Muir from the Frankfurt Zoological Society and six of my men, we tried to enter the rebel-held territory to talk to the rebel commanders. We were turned back at the first rebel checkpoint on the road. Our only chance at this stage was to get through to higher command and get them to stop their men from killing the gorillas.

We were certain it was rebel leader Laurent Nkunda's men, because UN peacekeepers confirmed that no-one else had access to the area where the gorilla was killed. It was also clear that they know they shouldn't be doing it because they were trying to hide the evidence.

A second gorilla was killed, with the possibility that others had been shot. It was time to fetch the remains. We entered the valley and drove past a rebel camp, entrenched less than 250 metres from where we were. They were observing us, seemingly a little surprised. We came to a line of trees, and just beyond that was Bikenge, our destination. The site where the gorilla's remains were supposed to have been discarded was still about 500 metres away, but at that point we saw a group of over 20 rebel soldiers pacing down the hillside towards us. As we hadn't been able to get a message across that we were coming, the fair assumption was that they were not too friendly. We decided to move out fast, and retreated a couple of kilometres away. This is where our plan B kicked in.

We had sent in two of our trackers the day before and they had managed to get to the area and recover the gorilla's head. It was a terrible thing to have to see. They joined us and we moved out. We did this because we needed to identify the individual, and to bring back irrefutable proof that gorillas were being killed. We learned a lot: the gorilla had been eaten for meat. His name was Karema, another solitary silverback that had been born into a habituated group. Above all, we learned that the remaining gorillas were extremely vulnerable – the rebels were after the meat, and it's not difficult for them to find and kill them.

We finally had a meeting with one of Laurent Nkunda rebel commanders, to discuss the gorilla killings and to explain that this has to be stopped. We headed out for Jomba, one of the key gorilla sites close to the Uganda border where the rebels have their headquarters. Shortly after our arrival at 10.30am, a company of men came striding down the hilltop in camouflage gear, most of them carrying heavy weapons and rocket launchers. Quite a few were also carrying spears too.

I met Colonel Makenga of the rebel forces and explained who the rangers were, what we were trying to achieve in the park, and how important it is to protect the mountain gorillas and other wildlife, even during times of war. I requested access to the Patrol Posts in the gorilla sector so that my rangers could search for the gorilla groups and establish their status. Col. Makenga granted my request.

This was all in January. Then in June, Kabirizi, our biggest group of mountain gorillas, was attacked by an armed group. After hearing three gunshots, my rangers in the Gatovu Patrol Post searched the forest for many hours and found the body of a breast-feeding mother called Rubiga. She had been shot in the head, execution-style. The rangers recovered a two month-old baby who was still attached to the mother's breast.

The baby was brought to Goma, and my rangers in the Mikeno Sector began conducting regular monitoring activities of the Kabirizi family. There was one adult female missing from the family – Lesenjina. She has a baby called Mutazimiza who had been seen being transported by his older brother Tumaini. We do not know for sure what happened to Lesenjina. We have not found a body so we cannot know if she has died or disappeared. We continue to look.

In July, four gorillas from the Rugendo group went missing. And our fears were confirmed when a silverback called Senkekwe, was found killed. The four were carried on stretchers for four hours back to Bukima with the help of about 70 people from the villages.

We also know that three females were killed: Unesi, who had a 2 year old baby who has disappeared; Mburanumwe was a young female that was pregnant and was about to have her first baby; and lastly Safari, whose baby Ndeze was born earlier this year. Safari was killed with a bullet through the chest. Her killing broke my heart. When her baby was born in February this year, we took it as a sign of better things to come. Baby Ndeze was seen fleetingly today with her elder brother who is trying to protect her. That he rescued her from her dead mother's body is incredible. But he cannot feed her because she is still breast-feeding, so she will be badly dehydrated, and is likely to die. We are trying to find them, but it is incredibly difficult in the forest at the moment.

If the Silverback is killed by poachers, it has a catastrophic effect on the rest of the group, the group itself is usually destroyed, and the trauma is felt for years afterwards.

• Paulin Ngobobo works with WildlifeDirect, a conservation group based in the DRC and Kenya that supports the rangers working in Virunga National Park